The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Prior vehicular emission monitoring systems utilize emission monitoring oxygen sensors on either end (i.e., upstream and downstream) of a catalytic converter for monitoring converter performance. With recent governmental regulatory changes, automotive manufacturers are now requiring mid-bed sensors, i.e., sensors mounted between two bricks of catalytic material carrying substrates inside the converter housing. This arrangement yields improved converter performance measurement, because the upstream substrate catalyst tends to degrade faster than the downstream substrate catalyst.
Providing a mid-bed sensor mounting arrangement has, in the past, raised problems of management of heat radiating from the converter shell in the shell area between the substrates. There is therefore seen to be a need in the converter art to provide a mid-bed sensor mounting arrangement which additionally provides insulation between exhaust flow and the converter shell located in the mid-bed region.